diff options
| author | Anna-Maria Behnsen <anna-maria@linutronix.de> | 2024-10-09 10:29:11 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-10-25 19:49:15 +0200 |
| commit | 351619fc99883d22ba1018b5914ae717bfef4221 (patch) | |
| tree | 5b4dfcce626198bf38506e44f6b38d8e1bd92eca /kernel/time/timekeeping.c | |
| parent | timekeeping: Rework timekeeping_inject_offset() to use shadow_timekeeper (diff) | |
| download | linux-351619fc99883d22ba1018b5914ae717bfef4221.tar.gz linux-351619fc99883d22ba1018b5914ae717bfef4221.zip | |
timekeeping: Rework change_clocksource() to use shadow_timekeeper
Updates of the timekeeper can be done by operating on the shadow timekeeper
and afterwards copying the result into the real timekeeper. This has the
advantage, that the sequence count write protected region is kept as small
as possible.
Convert change_clocksource() to use this scheme.
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/all/20241009-devel-anna-maria-b4-timers-ptp-timekeeping-v2-18-554456a44a15@linutronix.de
Diffstat (limited to 'kernel/time/timekeeping.c')
| -rw-r--r-- | kernel/time/timekeeping.c | 18 |
1 files changed, 7 insertions, 11 deletions
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 7e865f057935..f77782f557ce 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1627,9 +1627,7 @@ static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset) */ static int change_clocksource(void *data) { - struct timekeeper *tk = &tk_core.timekeeper; struct clocksource *new = data, *old = NULL; - unsigned long flags; /* * If the clocksource is in a module, get a module reference. @@ -1645,16 +1643,14 @@ static int change_clocksource(void *data) return 0; } - raw_spin_lock_irqsave(&tk_core.lock, flags); - write_seqcount_begin(&tk_core.seq); - - timekeeping_forward_now(tk); - old = tk->tkr_mono.clock; - tk_setup_internals(tk, new); - timekeeping_update(&tk_core, tk, TK_UPDATE_ALL | TK_MIRROR); + scoped_guard (raw_spinlock_irqsave, &tk_core.lock) { + struct timekeeper *tks = &tk_core.shadow_timekeeper; - write_seqcount_end(&tk_core.seq); - raw_spin_unlock_irqrestore(&tk_core.lock, flags); + timekeeping_forward_now(tks); + old = tks->tkr_mono.clock; + tk_setup_internals(tks, new); + timekeeping_update_from_shadow(&tk_core, TK_UPDATE_ALL); + } if (old) { if (old->disable) |